I've not heard that rumor. Just that the price will go down very slightly, but no appetizers and no tips will be included. Also that there will be a "deluxe" plan and a wine plan. I honestly doubt they'd make people staying onsite buy the DDP.
There are 30,000 Disney-owned hotel rooms. Suppose two guests per. That's 60,000 people. Does anyone think that the total TS capacity on resort is 60,000 meals per day?
Look at what happens during free dining. The restaurants are completely over-run, yet the parks and resorts still aren't full, nor is everyone who is there actually on the plan.
If everyone HAD to have a DDP the resturants would not be able to cope, with only some people having it they are struggling. I don't think they would do this.